A method is presented adopting the phase coexistence technique within molecular dynamics simulations to identify the liquidus and solidus of binary systems. The Compositional Moving Interface method is applied to the case study of the Cu–Ni system and compared against a thermodynamic end-point model where the input parameters are determined using the same MD potential. This is a simple and powerful method to predict the solidus and liquidus boundary of a binary phase diagram for mixed systems calculated from the dynamics of a simulation.